During Dave's next term at school there was much trouble with one of the teachers, who was harsh and unsympathetic, and as a result some of the boys ran away. It was Dave who went after them and who, in spite of a fearful flood, managed to bring them back and make them face the music. Then came the graduation exercises at Oak Hall, Dave receiving high honors. Our hero had promised Roger Morr that he would pay the senator's son a visit. During this time Dave heard of a gold mine belonging to Mrs. Morr which had been lost because of a landslide. All the boys went out West in an endeavor to relocate this claim. Their adventures were both numerous and hazardous, and once more Dave fell in with Link Merwell. But all went well with our young friends, and they had a glorious time visiting Yellowstone Park and other points of interest. "Now you fellows have got to come on a little trip with me," Phil Lawrence had said after he, Dave and Roger, with the others, had returned again to the East. There was a small steamer belonging to Mr. Lawrence that was tied up at Philadelphia getting ready for a trip to Portland, Maine. The voyage up the Atlantic coast had been productive of several unlooked-for results. On the way those on the boat had discovered another vessel in flames. This was a craft being used by a company of moving-picture actors, and some of the latter in their panic had leaped overboard. Our young friends, as well as some of the sailors on their ship, had gone to the rescue; and among others had picked up a young man, Ward Porton by name. Much to the surprise of Roger Morr and Phil Lawrence, Ward Porton had looked a good deal like Dave. Not only that, but many of his manners, outwardly, were similar to those of our hero. Following the trip up the coast, it had been decided by the Wadsworths and the Basswoods to spend part of the summer in the Adirondacks, at a spot known as Mirror Lake. Thither all of the young people and some of the older ones went to enjoy themselves greatly and to meet with a number of strange happenings, all of which have been related in detail in the volume preceding this, entitled "Dave Porter at Bear Camp." The boys fell in with a wild sort of creature whom they at first supposed to be a crazy uncle of Nat Poole, the son of a miserly money lender of Crumville. Later, however, the man was found to be a missing uncle of Phil Lawrence, for whom the Lawrence family had been seeking for a long time. Although Dave Porter did not know it at the time, the moving-picture company to which Ward Porton belonged had also numbered among its members Dave's former school enemy, Link Merwell. From Link, Ward Porton, who was the good-for-nothing nephew of a Burlington lumber dealer, had learned the particulars concerning Dave's childhood and how he had been placed in the Crumville poorhouse and listed as of unknown parentage.